Players take turns placing their pyramids on an 8x8 grid (chessboard). Then players in turn, drop pieces, placing them on their side facing away from them. If the pyramid is still facing away from them at the end of the game, they earn points for it, depending on size. When a piece is dropped, it can "turn" one or more other pieces - that is, change the direction of other pieces along the path in which it is pointing, so that those pieces are also pointing away from the player who dropped the piece. The number of pieces a piece can turn is dependent upon its size; a large pyramid can turn three other pieces, a medium two, and a small piece only one.
On your turn, you choose a piece to drop, and then you turn the correct number of pieces in front of the piece you just dropped, so that they are all pointing away from you.
However: only pieces that are lying down are turned. Pieces that are standing upright are left standing upright. This means that in some cases, particularly early in the game, you won't get to turn any pieces even if you drop a large piece.
Rules can be found on Wunderland.com
Game System
Icehouse Pieces